|
|
Egg cells are about the size of a grain of sand. They are formed inside of a female's ovaries before she is even born.
Hippocrates noted that blood separates into four differently colored liquids when removed from the body and examined: a pure red liquid mixed with white liquid material with a yellow-colored froth at the top and a black substance that settles underneath; he named these the four humors (for blood, phlegm, yellow bile, and black bile).
HIV testing reach is still limited. An estimated 40% of people with HIV (more than 14 million) remain undiagnosed and do not know their infection status.
Blood in the urine can be a sign of a kidney stone, glomerulonephritis, or other kidney problems.
Human kidneys will clean about 1 million gallons of blood in an average lifetime.